Sea's Tinkerings
At third level, you've mastered the art of working with sea prism and seastone-infused objects. At level 3, you gain access to the first Tier upgrade on the Seastone Infusion list. You may add the infusion to your masterwork weapon for free but to add it onto other weapons you must spend 10DT and the materials listed for each tier. Additionally, you gain access to the following Jury Rigs:
Suppression Beacon: This structure occupies a 10ft square. Devil fruit users that start their turn or move within 15 ft of the Suppression Beacon must make a Constitution Saving Throw or gain the Suppressed effect for 1d4 turns. At 11th level, the area that the suppression beacon affects is 35ft, the Constitution Saving Throw is made with a -4 to the save, and the effect lasts for 1d6+1 rounds.
Prism of Your Own Making
At 6th level, your sea prism experimentation has allowed you the ability to create special upgrades to your armor and weapons. You gain access to special upgrades, also known as Prism Upgrades, that you may add by spending 3DT and 25k per tier of upgrade you try to add to your weapons and armor. You can only add T1 upgrades when gaining this feature but gain 1 tier higher upgrades from the Prism upgrades list every time you would gain a new subclass feature. These Prism Upgrades act like masterworks, they do not function if they were given to other people that aren’t yourself as these signify your expertise in your craft. They do however, count as upgrades for upgrade limits.
Prism Upgrade Tier 1
Suppression Armor: Your armor is considered to have Seastone made into the armor which can only be applied to medium or heavy armor. This does not count towards an upgrade slot but acts as a check for features that require Seastone Armor.(Armor Upgrade)
Seastone Coat: You’ve been able to coat the outside of your weapon with a fine layer of Seastone dust. You gain 1 additional die of damage against DF users.(Weapon Upgrade)
Sight of the Sea: If a feature from a DF would decrease or remove your sight, you still maintain 15 ft of any 1 vision you have.(Armor Upgrade)
Prism Upgrades Tier 2
Now you Sea me, now you Don’t: (Armor Upgrade) Using the reflective nature of the sea, you’ve learned to hide your presence. As an action ,you may become invisible to all DF users for 1 minute with no sight able to see you.
Seastone Caltrop Dropper: (Melee Weapon Upgrade) You were able to attach a holder of Seastone Caltrops which has 5 charges which recharge on a long rest. After making an attack, you may spend 1 use of the caltrops to drop a number of them into a space within your weapon’s reach in a 5ft square. If a creature starts their turn on that square or moves into it the first time on their turn, they must roll a Constitution Save against your Special DC or become Suppressed. They must spend a bonus action to remove the caltrop.
Sea’s Benefit: (Armor Upgrade) By the grace of the sea, you’ve gained insight from the waves. Twice per long rest, you may add 1d6 to a skill check you have proficiency in.
Prism Upgrades Tier 3
Rolling in the Deep: (Weapon Upgrade) Your weapon allows you to summon a bit of the sea’s force with it. When you hit a creature, you may push it 10ft back or knock them prone(your choice). You also deal an additional 1 die of damage.
Creaking Tide: (Armor Upgrade) Your weapon creaks with stress but also with protection. While your armor is considered Seastone, you have +3 AC against DF users and +2 AC against anyone else.
Emerald Splash: (Weapon Upgrade) Instead of your weapon attacking against 1 target, you may instead use it as a wave against all creatures. Instead of 2 attacks, you may make an 1 attack roll against all creatures in a 15ft cone beginning from you, getting advantage on DF users.
Prism Upgrades Tier 4
Unreachable Depths: (Armor Upgrade) You’re able to give your armor the protection of the depths itself, making DF users feel woozy even trying to come near you. All attacks made by DF users within 10ft of you have disadvantage.
Flash of Steel: (Weapon Upgrade) The Seastone allows for the flash of the sea, moving and attacking in its mysterious ways. A number of times equal to half your proficiency bonus(rounded down), you may choose to attack with advantage. If done against a DF User, the attack does an additional 2 dice of damage.
Pacific Edge: (Weapon Upgrade) This upgraded version of Emerald Splash is the summoning of sea energy in a devastating wave. Instead of making 2 attacks, you may instead make 2 attacks that target all creatures within a 30 ft cone that starts from you, getting advantage on DF users and 2 additional damage dice.
Overdrive
At 10th level, you are able to send your item into overdrive. As a bonus action, if you are wielding a seastone-enhanced weapon or armor, you may release the true essence of the stone to create a 10ft radius aura centered on the item that lasts for 1 minute. Any DF user that starts their turn in the area or moves into it for the first time on their turn must make a Constitution Saving Throw with a -2 to the save and be suppressed on a failure for 2 turns. As well, if you activate this on your armor, it gains +1 to AC and if you use a weapon for activation, it gains a +2 to attack and damage rolls. You may only use this ability twice per long rest.
Stress to Suppress
Your work with the unique stones and energies has led to you being able to activate their natures vin moments of danger. At level 14, you're able to release condensed Sea Prism in a way that either attempts to Suppress or Disrupt an enemy. A number of times equal to half your proficiency bonus(rounded up), you may try to activate the energy of your sea stone as a reaction to being hit by a Haki User or Devil Fruit user. They must make a Constitution Saving Throw versus your Special Technique Save DC becoming Suppressed or Disrupted (your choice) for 1d6+2 rounds. While affected by this feature, the Suppressed or Disrupted creature gains 1 level of Exhaustion. As well, while affected, you gain a +2 to attack and damage rolls against them.
Perfect Blend
At 18th level, You've perfected your sea-stone and sea prism use into, allowing it to function as pure ocean energy. You may now use your Overdrive feature 4 times per long rest and use Stress to Suppress and extra 2 times. As well, you’ve learned how to incapacitate the weak and strong DF users by your refined seastone construction. While applying Suppressed to a DF user, you may stack Suppressed on them though this does not increase the effects of suppression. If a DF user gains more than half of their proficiency modifier(rounded up) in suppressed stacks, they must make a Constitution Save at disadvantage against your Special DC+half your proficiency bonus(rounded down) or become incapacitated for one minute. After this ability activates, the amount of stacks of Suppressed resets to 1. Once a creature succeeds this save twice, they are considered immune to its effects for 24 hours.